The Evoloution Of The Atmosphere Flashcards
What happened when things on the original molten earth cooled down a bit?
A thin crust formed, but volcanoes kept erupting
How were the oceans and atmosphere formed?
The volcanoes gave out lots of gas - including carbon dioxide, water vapour and small amounts of other gases. The oceans formed when the water vapour condensed.
What happened to a lot of the early CO2?
It dissolved into the oceans
What happened when, later, marine organisms developed?
They took in some of the CO2. When they died the organisms were buried under layers of sediment and the CO2 became locked up in carbonate rocks.
Were the green plants that evolved happy in the CO2 atmosphere?
Yes
What did these new green plants do?
Removed CO2 from the air and produced O2 by photosynthesis. This caused the oxygen level to gradually INCREASE.
What did the build up of oxygen in the early atmosphere do?
Killed off some early organisms that couldn’t tolerate it, but allowed other, more complex organisms to evolve and flourish.
What else did the oxygen create?
The Ozone layer. The Ozone layer blocks harmful rays from the sun and enabled even more complex organisms to evolve.
Is there a lot of CO2 in the atmosphere today?
No, there’s very little
What percentage of nitrogen is in our atmosphere today?
78%
What percentage of oxygen is in our atmosphere today?
21%
What percentage of argon is in our atmosphere today?
Nearly 1%
What percentage of CO2 is in our atmosphere today?
0.04%
Is there water vapour in the atmosphere today?
Yes
What was the earths surface originally?
Molten
